Coil forming method and apparatus for zipper fasteners



Feb. 16, 1965 'J BURBANK 3,170,014

. E N m I-ig.

I I INVENTOR John E. Burbank H BY ' 3,170,014 j COIL FORMING METHODEA-ND APPARATUS FOR ZIPPER FASTENERS. 1 John E. Burbank, Stamford, .Conn.,,,assigur IQ-,SCOVil] Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Filed may, hast ns. 112,07 4Claini's. or. 264-74 My invention relates to method and apparatus for forming coils, especially from a filament of plastic material, and is useful primarily in'the manufacture of plastic coil type zippers. I v

The apparatus involved is of the same general type as that disclosed inmy co-pending application Serial Number 161,960 filed December2 19 ,That pp ic t discloses the free-formingcf, coils to be received and shaped in the cavities of aseries. of dies. 7

In the presentinvention,,theplastic filament is also supplied to suchawseries 10f diesin, coil form and without the use of a mandrel for. winding the coil;

One important difference is that the filament is fed out of the guide which is preferably a nozzle directed at such an angle that it is directly in line with the coil to be formed. Such guide nozzle is fixed to a rotating frame carrying the filament supply so that as the coil emerges, it assumes naturally the shape of the coil desired. The end of the discharge nozzle is spaced slightly fromthe center axis of the rotating supply and the nozzle extends in the direction transversely to the axis of the rotation and preferably forwardly thereof at an angle equal to the pitch angle of the coil so that the angle of emergence is tangential to or in line with the coil to be formed. Thus, there is a minimum change of direction and minimum forces applied resulting in the simplest form of bending action coupled with a positive feed rate.

Means are also arranged for engaging each convolution as formed with one of a series of recesses in a row of dies. For this purpose, I preferably employ a pusher engaging with a portion of each convolution as formed upon each rotation of the supply source and nozzle so as to advance such portion of the convolution into the positionwhere it is caught in a die.

In the accompanying drawing, I have shown for purpose of illustration one embodiment which my invention may assume in practice. In the'drawing:

FIG. 1 is a schematic view in perspective and generally in central section showing the improved method and apparatus;

FIG. 2 is a partial sectional view near the discharge end of the apparatus;

FIG. 3 is a detail illustrating cam-actuation of the pusher; and,

FIG. 4 is a partially sectionalized side view of some of the dies for receiving the coil from my improved method and apparatus.

The filament F comes from a supply source, herein shown as a spool 5 through a guide tube 6 over guide pulleys 7 and 8 and driven feed pulleys 9 and 10 to a discharge guide nozzle 11. The rotating frame, mounting the filament source at one end and the nozzle and feed pulleys at the other end, turns on a shaft 12 journalled in a long bearing in the stationary support block 13. This frame is rotated by a suitable source of power through the means of a belt 14 and pulley 15 fixed to the shaft 12. The supply spool 5 is mounted on an extension shaft 16 of the rotating frame and has a flange 17 bearing against the end face of the frame, and a suitable nut is provided to hold such flange in frictional contact with the frame. In this manner, the filament supply spool 5 rotates bodily with the frame in general but may rotate relative thereto to permit the unwinding of the filament. The guide tube in a forward position 29 of the rotating frame.

3,170,014 Patent ed Feb. 16, 1965 6 is fixed in, a suitable manner in the rotating frame as is thedisch arg'e, nozzle 11 and guide pulleys] and 8 and feed pulleys 9 and 10 Thus, the filament, guides and feeding means all rotateabout a common axis so that as the filament emerges, it naturally assumes the shape of a helix.

The nozzle 11 has its discharge end spaced slightly from such axis of rotation and extends in a direction generally transverse to that axis but in .a forward direction from a plane normal to the axisat an angle equivalent to the pitch angle of the coil being formed. The entrance end of the nozzle guide ll is located between the inner surface of belt 34 and outer surface of pulley It} so as to receive the filament asit is delivered from the feed pulley 10.

The series of dies for receiving the coil are not shown in full, since they do not in themselves form a part of the present invention. In general, they comprise die pieces 18 carried by the ends of flexible spokes 19, and each die piece has suitable cavities 20 in their mating faces. These die pieces are in turn spread apart to open the die cavities for receiving a coil convolution at the proper time. This is accomplished by suitable mechanism such as described in my aforesaid application.

In order to make each convolution engage positively in one of the die cavities, I provide a pusher in the form of a bar 21 reciprocally mounted in the'shaft 12. This pusher bar is actuated by a spring 22 to move it forwardly so that its narrow end 23 engages a portion of the coil at the proper time and pushes it into an open die cavity which is in line with the pusher bar end 23. Thisnbar is retracted by a plate cam 24 fastened to the stationary support block 13 which as seen in the detail, has a cam notch 25 engaged by a lug 26 on the pusher bar and of course, the cam is so designed as to operate the pusher bar in properly-timed sequence upon each rotation of the frame.

The gearing for operating the feed pulleys 9 and 10 is shown only schematically since it is substantially the same as that employed in my aforesaid application. In general, it comprises planetary gears 27 and 28 fixed to the shafts carrying pulleys 9 and 10, both of which are journalled These planetary gears are driven by a suitable gear chain which may include a gear 30 keyed to the central shaft 12 of the rotating frame meshing with a gear 31 journalled to the stationary block 13 carrying a stepped down portion 32 meshing with a gear 33 which is free to turn on the central shaft 12 and this large gear 33 in turn, drives the gears 27 I and 28. The gearing is such as to advance the filament to a series of dies presenting a series of cavities, each of which is adapted to receive a portion of each convolution of the coil, .which comprises (a) positively feeding from a bodily rotating source a filament and pushing through a guide rotating about the same axis as said source, a length of filament equal to that required in one complete convolution of the coil to be formed, upon each complete rotation of said guide;

(b) discharging the filament from the guide in a direction tangentially of the coil and at the pitch angle thereof whereby the filament naturally assumes the shape of a helix; and,

(c) engaging each convolution as it is shaped, in one of the cavities of said series of dies.

A process of supplying a plastic filament in coil form to a series of dies presenting a series of cavities each of which is adapted to receive a portion of each convolution of the coil, which comprises (a) positively feeding from a bodily rotating source of filament and pushing through a guide rotating about the same axis as said source, a length of filament equal to that required in one complete convolution of the coil to be formed, upon each complete rotation of said guide;

(b) discharging the filament from the guide in a direction tangentially of the coil and at the pitch angle thereof whereby the filament naturally assumes the shape of a helix; and,

(c) pushing a portion of each convolution as it is shaped, into one of the cavities of said series of dies.

3. A machine for supplying a plastic filament in coil form to a series of dies presenting a series of cavities each of which is adapted to receive a portion of each convolution of the coil, which comprises (a) a frame mounted to rotate on an axis;

(b) a filament source carried by said rotating frame;

(0) a discharge nozzle fixed on said frame having its discharge end spaced from said axis and the direction of said nozzle being generally transverse to such axis whereby the filament emerges in a direction tangentially of the coil convolutions; and

(d) means for positively feeding the filament from said source and pushing the same through said nozzle, said feeding means including a plurality of feed pulleys, a belt running around said pulleys, means for directing the filament from said source to the outer surface of one of the pulleys, the entrance end of said nozzle being located between the inner surface of the belt and outer surface of another of said pulleys to receive the filament and guide it to the discharge end of said nozzle.

4. A machine as defined in claim 3 and (e) a pusher operable upon each revolution of said frame to engage a portion of each coil convolution as 7 formed and advance it to a position to be received by a die cavity.

References Cited in the file of this patent UNITED STATES PATENTS 2,105,338 Sunderland Jan. 11, 1938 2,173,096 Campbell Sept. 19, 1939 2,363,826 Yellin Nov. 28, 1944 2,509,500 Howey May 30, 1950 2,685,362 Larsen Aug. 3, 1954 3,052,922 Wilcken Sept. 11, 1962 3,054,149 Streicher Sept. 18, 1962 

1. A PROCESS OF SUPPLYING A PLASTIC FILAMENT IN COIL FORM TO A SERIES OF DIES PRESENTING A SERIES OF CAVITIES, EACH OF WHICH IS ADAPTED TO RECEIVE A PORTION OF EACH CONVOLUTION OF THE COIL, WHICH COMPRISES (A) POSITIVELY FEEDING FROM A BODILY ROTATING SOURCE A FILAMENT AND PUSHING THROUGH A GUIDE ROTATING ABOUT THE SAME AXIS AS SAID SOURCE, A LENGTH OF FILAMENT EQUAL TO THAT REQUIRED IN ONE COMPLETE CONVOLUTION OF THE COIL TO BE FORMED, UPON EACH COMPLETE ROTATION OF SAID GUIDE; (B) DISCHARGING THE FILAMENT FROM THE GUIDE IN A DIRECTION TANGENTIALLY OF THE COIL AND AT THE PITCH ANGLE THEREOF WHEREBY THE FILAMENT NATURALLY ASSUMES THE SHAPE OF A HELIX; AND (C) ENGAGING EACH CONVOLUTION AS IT IS SHAPED, IN ONE OF THE CAVITIES OF SAID SERIES OF DIES. 